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#!/usr/bin/python
# IVLE - Informatics Virtual Learning Environment
# Copyright (C) 2009 The University of Melbourne
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
import optparse
import os
import stat
import sys
import shutil
import ivle.config
import ivle.jailbuilder.debian
class UnsafeJail(Exception):
pass
usage = """usage: %prog [options]
(requires root)
Builds or updates the base IVLE jail."""
# Requires root
if os.getuid() != 0:
print >> sys.stderr, "This script requires root privileges to run"
sys.exit(1)
conf = ivle.config.Config()
build_path = conf['paths']['jails']['template_build']
# Parse arguments
parser = optparse.OptionParser(usage)
parser.add_option("-r", "--recreate",
action="store_true", dest="recreate",
help='''Completely recreate the jail - don't just update its IVLE code.
Be warned, this may download hundreds of megabytes!''')
parser.add_option("-u", "--upgrade",
action="store_true", dest="upgrade",
help='''Apply any package updates in the jail.''')
parser.add_option("-m", "--mirror",
action="store", dest="apt_mirror",
help="Sets the apt mirror.", default=conf['jail']['mirror'])
parser.add_option("--python-site-packages",
action="store", dest="python_site_packages",
help="Path to Python site packages directory inside the jail.",
default=None)
(options, args) = parser.parse_args(sys.argv)
if os.geteuid() != 0:
print >> sys.stderr, "Must be root to run buildjail."
sys.exit(1)
if not options.recreate and not os.path.exists(build_path):
print >> sys.stderr, "No jail exists -- please rerun with -r."
sys.exit(1)
if (options.python_site_packages is not None and
options.python_site_packages[:1] not in (os.path.sep, os.path.altsep)):
print >> sys.stderr, "python-site-packages must be an absolute path."
sys.exit(1)
if options.recreate:
options.upgrade = True
# Create the jail and its subdirectories
# Note: Other subdirs will be made by copying files
if options.apt_mirror is not None:
os.environ['MIRROR'] = options.apt_mirror
# Print a final warning to the user that this is a potentially-expensive
# operation
recreating = "Re-creating" if os.path.exists(build_path) else "Creating"
print_mirror = options.apt_mirror or 'http://archive.ubuntu.com/ubuntu'
print """%s jail from %s
Be warned, this may download hundreds of megabytes!
If this is the wrong source, please cancel now (note that it is too late to
save the existing jail; you will have to rebuild the jail from scratch now).\
""" % (recreating, print_mirror)
os.system('rm -rf --one-file-system ' + build_path)
ivle.jailbuilder.debian.debootstrap_create_jail(conf['jail']['suite'],
build_path, mirror=options.apt_mirror)
ivle.jailbuilder.debian.apt_update_cache(build_path)
# Minimal required packages
ivle.jailbuilder.debian.apt_install(build_path,
['python', 'python-cjson', 'python-svn', 'python-configobj'])
ivle.jailbuilder.debian.apt_clean(build_path)
if options.upgrade:
# Run apt-get update, apt-get upgrade and apt-get clean.
ivle.jailbuilder.debian.mangle_sources_list(build_path, clobber=True)
ivle.jailbuilder.debian.mangle_sources_list(build_path, lines=[
'deb %s %s%s %s' % (options.apt_mirror, conf['jail']['suite'],
pocket, ' '.join(['main', 'universe']))
for pocket in ('', '-updates', '-security')])
# Add any extra site apt sources.
if conf['jail']['extra_sources']:
ivle.jailbuilder.debian.mangle_sources_list(build_path,
conf['jail']['extra_sources'])
# Add any extra site apt keys.
if conf['jail']['extra_keys']:
ivle.jailbuilder.debian.apt_add_key(build_path,
conf['jail']['extra_keys'])
ivle.jailbuilder.debian.apt_update_cache(build_path)
ivle.jailbuilder.debian.apt_upgrade(build_path)
# Install any extra site packages.
if conf['jail']['extra_packages']:
ivle.jailbuilder.debian.apt_install(build_path,
conf['jail']['extra_packages'])
ivle.jailbuilder.debian.apt_clean(build_path)
# Configure locales to allow en_US.UTF-8 (which IVLE uses)
ivle.jailbuilder.debian._execute_in_chroot(build_path,
['locale-gen', 'en_US.UTF-8'])
if conf['jail']['devmode']:
# Copy all console and operating system files into the jail
services_path = os.path.join(conf['paths']['share'], 'services')
jail_services_path = os.path.join(build_path, services_path[1:])
if os.path.exists(jail_services_path):
shutil.rmtree(jail_services_path)
shutil.copytree(services_path, jail_services_path)
# Also copy the IVLE lib directory into the jail
# This is necessary for running certain services
# ivle_site_packages is the IVLE install location outside the jail
ivle_site_packages = os.path.dirname(ivle.__file__)
if options.python_site_packages is None:
# Get the site packages from the IVLE install location *OUTSIDE* the
# jail. Warning! This only works if you have the same Python site
# packages directory inside and out (ie. same Python version).
# If not, you should use --python-site-packages.
jail_site_packages = os.path.join(build_path, ivle_site_packages[1:])
else:
# User-specified site packages
jail_site_packages = os.path.join(build_path,
options.python_site_packages[1:], "ivle")
if os.path.exists(jail_site_packages):
shutil.rmtree(jail_site_packages)
shutil.copytree(ivle_site_packages, jail_site_packages)
# And finally copy in /etc/hosts, /etc/resolv.conf and /etc/hostname,
# so name resolution is less unlikely to work.
shutil.copy(
'/etc/resolv.conf', os.path.join(build_path, 'etc/resolv.conf'))
shutil.copy('/etc/hosts', os.path.join(build_path, 'etc/hosts'))
shutil.copy('/etc/hostname', os.path.join(build_path, 'etc/hostname'))
# Make /tmp and /var/lock un-world-writable. /tmp will be mounted over,
# and /var/{lock,tmp} should die.
for path in ('tmp', 'var/lock', 'var/tmp'):
path = os.path.join(build_path, path)
os.chmod(path, os.stat(path).st_mode & ~stat.S_IWOTH)
# Verify that nothing in the jail is world-writable.
# We don't want students to write into places that others can see.
try:
for path, dirs, files in os.walk(build_path):
for dname in dirs:
d = os.path.join(path, dname)
if os.path.islink(d):
continue
if os.stat(d).st_mode & stat.S_IWOTH:
raise UnsafeJail(d)
for fname in files:
f = os.path.join(path, fname)
if os.path.islink(f):
continue
if os.stat(f).st_mode & stat.S_IWOTH:
if (os.path.dirname(f) == os.path.join(build_path, 'dev') and
os.path.basename(f) in ('ptmx', 'null', 'tty', 'full', 'zero',
'random', 'urandom')
):
continue
raise UnsafeJail(f)
except UnsafeJail, e:
print >> sys.stderr,"""Error: Jail contains world writable path: '%s'.
This is a security vulnerability as jail template contents are shared between
users. Please either make this path world unwriteable or remove it from the
jail."""%str(e)
sys.exit(1)
# Copy jail template build to actual jail template
template_path = conf['paths']['jails']['template']
if os.spawnvp(os.P_WAIT, 'rsync', ['rsync', '-a', '--delete',
build_path + '/', template_path]) != 0:
print >> sys.stderr, "Jail copying failed."
sys.exit(1)
# Now mangle things a bit, so we can bind-mount the user bits in.
# /etc/passwd and /etc/ivle/ivle.conf need to be symlinks to somewhere in /home
os.rename(os.path.join(template_path, 'etc/passwd'),
os.path.join(template_path, 'home/.passwd')
)
os.symlink('../home/.passwd', os.path.join(template_path, 'etc/passwd'))
os.makedirs(os.path.join(template_path, "etc/ivle"))
os.symlink('../../home/.ivle.conf',
os.path.join(template_path, "etc/ivle/ivle.conf"))
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